The present application relates to a transmission scheme for text-based information such as, for example, data-carousel text-based information broadcasting an example for which is the XML-based low-profile information service Journaline (R).
Text-based information signals carrying text-based information content distributed to information objects are used, for example, in data-carousel text-based information broadcasting systems, in data transmissions where the textual information contents are transferred on demand, or in address-based data transmissions directed to specified addressees which may or may not ordered the transmission by demand.
Data carousel text-based information broadcasting, for example, enables text-based information to be distributed to a huge amount of users while keeping the technical overhead reasonably low. For example, no uplink or feedback signals from the receivers to the broadcast transmitter is needed. In order to enable the users to individually navigate through the information content provided by the broadcast signal according to their personal preferences, the whole information is divided-up into objects referring to other objects, thereby enabling interactively navigating through the resulting linked arrangement of objects. For example, menu objects enable the user to select, among menu items, in order to proceed from one object to the other.
When considering the transmission of a text-based information signal, care should be taken to distinguish between the transport layer on the one hand and the application layer on the other hand. That is, the text-based information service provides for the text information objects into which the text-based information content is distributed. Obviously, these information objects may have different lengths. These information objects have to be transmitted to the service recipients. This falls into the responsibility of the transport layer system, i.e. the system interfacing the service transmitter and the service recipients/receivers. The transport layer defines the way the data to be transmitted or transported is to be passed on from the application layer to the transport layer and how the data is then passed on from the transport layer to the application layer at the recipient's side. For example, the transport layer may expect to receive the data to be transmitted in form of packets. Alternatively, the transport layer may allow a stream of data to be passed on to the transport layer at the transmission's side. In case of text-based information transmission by way of information objects, the service recipient expects to receive the application layer data in units of information objects. This, in turn, means that the transport layer has to be able to cope with the maximum size of the information objects, allowed by the text-based information service. That is, the transport layer has to be defined such that the information objects of maximum size fit into the content section of the transport packet of the transport layer, or the transport layer has to be able to handle inbound information objects having a size greater than the maximum size of the content section of the transport packets with then, at the recipient's side, re-combining the sub-portions of these information objects so that the fragmented transport is transparent for the service recipient.
This, however, means that the information service and the respective service receivers are merely applicable in connection with transport layer systems which comply with the afore-mentioned requirements. This, however, restricts the applicability of the respective service.